Thanks all,
Chris got me dialed in on getting a log from Per's driver. So tonight (it looks like the weather will be willing) I'll turn Meridian Flip on and post the log from Per's driver and the sgp log after the time jump. Unfortunately, as fate would have it, tonight will be my last shot for almost a month as scheduled travel will take me away from home. Hopefully the data from tonight will be enough to locate the problem [of course, we all know how it goes --- the automatic flip will just work tonight 
] I will triple check again tonight time; dst; lat/lon in the mount and computer. These have all been checked at least twice, but when things don't make sense sometimes when you go back and check that third time you find you had been seeing what you expected and not what was. But even if one of these were wrong I cannot imagine how that could cause a jump in the hour angle SGP tracks to decide when to flip. As I said before a really odd fact is the displayed "time to to flip" jumps way ahead to -3:59:31 one night and -3:59:26 another and then does not appear to change. I did note that an auto focus run seems to have happened just before the massive jump in HA. That could be coincidence or a clue. It sort of has the feeling of what would happen if SGP (I have no idea how it is implemented) has a pointer to the cell where HA is updated and somehow that pointer is overwritten so it now points to some random piece of memory. If the data I (hopefully) capture tonight does not lead to an answer, perhaps looking at the code and tracing the HA calculation backwards and then logging all its inputs in the SGP log as time passes might be helpful.
I appreciate the effort you all are putting in to fixing this. It will save me much sleep! Also,as an unfortunate aside, wanting to not stay up so late for a 3rd night in a row I tried to flip early (the 10Micron will flip 30˚ before if you want) . By inspection I believed, incorrectly, I could flip at 9˚ early. Oops, small mount crash. Turns out there is a adjustment screw that sticks out almost an inch from my FW and it was positioned perfectly to hit the tripod leg at the end of the flip. Other than a scratch on my new tripod, which shall serve as a reminder to not cut corners, all is well. I waited 20 minute to make sure it was safe, slewed back, re rotated (the impact had rotated the camera almost 21˚) and continued on. So, my brilliant move to get to sleep earlier kept me up another half hour past transit and cost me 5 subs. Geesh. I'm sure I am not the only one who can confess to such an error